Automatic brush spring adjuster



June 26, 1951 G. DEAKIN 2,557,947

AUTOMATIC BRUSH SPRING ADJUSTER Filed Aug. 14, 1947 4 Sheets-Sheet 1 INVENTOR. GERALD DEAKIN ATTORN EY June 26, 1951 G. DEAKIN AUTOMATIC BRUSH SPRING ADJUSTER Filed Aug. 14, 1947 4 Sheets-Sheet 2 DECREASE PRESSURE '3. /6 INCREASE /6 (Z/\/9 PRESSURE INVENTOR.

GERALD DEAKIN ATTO EY June 26, 1951 s. DEAKIN AUTOMATIC BRUSH SPRING ADJUSTER 4 Sheets-Sheet 5 Filed Aug. 14, 1947 FIG. 4.

INVENTOR. GERALD DEAKIN June 26, 1951 D K 2,557,947

' AUTOMATIC BRUSH SPRING ADJUSTER Filed Aug. 14', 1947 .4 Sheets-Sheet 4 'ERALD DEAKIN ATTORNEY Patented June 2 6, 1951 AUTOMATIC BRUSH SPRING ADJUSTER Gerald Deakin, New York, N. Y., assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application August 14, 1947, Serial No. 768,677

13 Claims.

This invention relates to new and useful improvements in thetensioning of springs and more particularly of electric contact springs, such as brush and relay springs of telecommunication systems.

The object of the invention is a machine for automatically and accurately adjusting the tension of a contact spring before it is installed'and thus avoid manualadjustments after installation.

Another object is a machine for registering the amount of pressure exertedby the contact surfaces of a spring.

According to the invention, an overtensioned sprirg is rigidly fixed in a holder and subjected to repeated blows that gradually reduce its tension to the desired amount. This amount is determined by tension measuring means, such as a pressure gauge, against which the spring bears. The gauge may either directly or indirectly control the operation of the means that delivers the detensioning blows and When the spring has the desired tension the gauge will automatically stop the detensioning operation.

These and other features of my invention will now be explained in greater detail in'the following description, appended claims and drawings, in which:

Fig. l is a perspective view of a spring;

Fig. 2 is a perspective view of a holder for the pr n Fig. 2a is a perspective view of a modification of the holder shown in Fig. 2.

Fig. 3 is a side elevation partly in section of the detensioning machine;

Fig. 4 is a section on line 33 of Fig. 3; and

Fig. 5 is a circuit diagram of the machine.

. A fiat spring such as a brush spring I is stamped out of a thin piece of metal, for instance, Phosphor bronze. The spring has a channelled central portion 2 provided with two ears 3 and 4 perforated at 5. Triangular arms 6 and 1 project from channel members 8 and 9 which formthe side walls of the channel 2. Edges It of arms 6 and 1 are turned up to stiffen the arms. The ends of the arms are formed into shoes II and [2 having rounded sides except for short flat contact surfaces l3 and I4 on the bottoms of the shoes. uThe brushes are initially overtensioned and, as exaggerated in Fig. 1, the planes of arms 6 and I intersect members 8 and 9 in angles a and b that are more acute than required. When 2 is fixed, the downward slopes of the arms with respect to it determine the amount of pressure shoes ll and 2 l2 apply to a surface they contact. The function of the presentmachine is to detension the spring by permanently bending back arms 6 and l, i. e. increase angles a and b, until shoes [I and I2 exert the required pressure.

A table l5 supports an anvil-like block IE on which spring I is deposited. Two cavities I? (Fig. 2) corresponding in size and spacing to holes 5 in the spring are provided in the block. Ledges l8 and I9 project parallel to table Hi from the center portion of block l6. Contact pins 20 and 2| respectively project through ledges l8 and I9 and are insulated therefrom. Tips 22 and 23 of pins 20 and 2| may contact shoes II and I2 of a brush spring resting with central portion 2 on block it. Plungers 24 and 25 also project through ledges I8 and I9 and are adapted to strike the bottom surfaces of arms fi and 1 near shoes II and I 2 to lift them to approximately the positions shown in dotted lines Fig. 3.

Holes 5 of the spring are aligned with cavities I! in the block so that central portion 2 may be clamped to the block with channel members 8 and 9 resting along opposite edges of a face plate 23 of a movable lever 21 pivotally mounted at 28 (Fig. 4) to a frame resting on table l5. By means of handle 29 lever 21 may be moved up and down with respect to central portion 2 of the spring. Pins 30 having a slightly smaller diam- 7 eter than holes 5 project from face plate 26 and are spaced so that when arm 2! is lowered the pins register with holes 5 and cavities H to secure the spring to the block. Thus the combination of face plate 26 and block It provides a holder which fixes spring I intermediate its ends. An alternative holder for the spring (Fig. 2a) has hooks 3| provided on face plate 26 now secured to lever 21 by rocker pin 32. Either ear 3 M4 is inserted between hoops 3| and face plate 26 with channel members 8 and 9 resting along opposite edges of the face plate. Holes 5 of the spring are aligned with holes I! in the face plate and pins 30 in block [6 register with the holes. The spring is thus first attached to the face plate and then lowered into contact with the block in-. stead of first placing the spring on the block and bringing the face plate into contact with the spring as above described.

The spring holder is held open and lever 2! is held in raised position by a spring 33 (Fig. 4), connected between the end opposite handle 29 andtab'le l 5. The holder may be closed and the lever locked in its lowered position by armature 34 of solenoid 35. Arn'lature 34 is held in' the raised position shown in dotted lines, Fig. 4, by a spring 38 attached between end 3'! of the armature and table [5. When solenoid 35 is energized over a circuit to be described below, armature 34 is pulled down against tension of spring 36 to the position shown in solid lines. A catch 38 projecting downward from lever 21 will just clear armature 34 when the armature is in raised position. "However, when the sole'-= noid is energized and lever 21 is in lowered posi-- tion, armature 34 engages catch 38 and locks the lever down until the solenoid dee'ner'g'izes, whereupon the lever and armature are permitted to rise. If solenoid 35 energ'izeswhileleverii'i fis in the raised position, thenend'39 fof iarriiaturr 34 blocks the downward movement of 'cat'ch' 3 8. Lever 21 must, therefore, remain inthera'isel-l position until the solenoid deenergizes T hus armature 34 functions as a lock-out as ware-S's lock-in element for spring I. r v I Shoes H and 12 of brush spring mense -60atacting tips 22 and 23"contact the ball {points ofoperating armsf40 and 4 I often'sion measuring gauges 42 and 43 mounted on plates 44 and 45 which are pivotally supported on frame 45 fastened to table l5. Pointers 41 and 48 of gauges 42 and 43 registerthe amount of pressure ap plied to arms 40 and 4!. Arms] 40 and 4! contact shoes H and I2 adjacent and outboard v pins and 2l and-are; preset to exert a given amount of pressure against the shoes by manually rotating plates 44 and 45. shown in Fig. 3 each gauge has been rotated via its-supporting plate until its arm 'exerts22 grams-pressure against the corresponding shoe.

The pressureto which itis desired that each shoe be detensioned is pre-set as above described on'each gauge and when the shoes havebee'n detensioned to the required pressure, arms 45 r and 4| prevent them from contacting tips 22 and 23 that control the energization of the detensioning means. 'Thepressureexerted by arms 4G and 4| is increased or decreased by rotating plates 44 and 45in-the'directions indicatedb'y the arrows in Fig 3. Thus gau'ges 42' and 43 control the amount of emanating to whicha shoe'will besubjected. H Y

Stops 49 and '50 on" plates 44'fa'n'd "45- prevent arms 46 and from inoving'beyond the-point that registers 15 grarnspressure on each -gauge. If the arms could move beyond "this *p'ointthey might notcontact shoes H and iZ-as'they are clamped to block l6. Other stops 5| anaemia provided on frame 48t'o preventinjuring-gauges 42 and 43 by rotating 'the'mbeyond man anmum pressure points as indicated by pointers 41 and as. V n

The height bf contacting tips '22 and "23 "with respect to block I 6 is accurately adjusted to 'd'uplicate the positiohsbf the brushshoeswhen in actual use. p M p The detensioning means consist *of" plungers24 and '25, respectively, pressed by s'fprings' 53 and" 54 mountedbetwee'n table I5 and 'yok'es 55-aiid 5fi, the latter being ia'stened to the'lower ends of plungers 24 and 25. Rollers sta ces-are secured within yokes 55 and 56 by 'suitablepins. The rollers are actuated by cams? SS and 'Gll 'eaeh coupled, respectively, to fi'e'iiible gears 64 andfGZ by a spacer 63and screws 54. Each camand flexible gear rotatesinfa bearing5 supported on a shaft 56 'andjfixed orr'the shaftby collarsf lil and set screws iiil. Flexiblegears 6i and 62 are controlled by clutches 55 and 10. When the clutch magnets are de e'nergized 'the' gears are 4 warped against clutch back stops H and I2 and when energized the gears under their own ten sion mesh with driving gears 13 and 14 mounted on drive shaft 15. Shafts 15 and 66 can serve one or more spring detensioning stations, only one of which is shown.

Each cam 59 and 60 is divided into a homing position and-nine operating positions (Fig. 4) having between them progressively raised camming surfaces, 16, 15, 16", etc. that actuate "plungers 24 and 25. The radius to each succeeding raised "surface is slightly greater than to the preceding one (r=radius in all positions; r+1 to 'surfa'ce ie', r' FZto'surface 16" etc.). The length of'the strokesofplungers 24 and 25 varies di- "teeny with the height of the camming surfaces,

therefore, the-amount of lift to be delivered by each camming surface must be determined beforehand. The lift must be such as to impart a slight permanent deformingof arms 5 and 'l by increasing angles wand 1). Turned up edges H) of each-arm give the arms overall rigidity which make them, including shoes and I2, respond as a 'whole to each blow of 'plungers 24 and 25.

The number of positions into which a cam may be divided need not be'tenfas shown, butmay be moreor less. V e w a e "At 'thecenter ofeach* position and near the periphery of each cam astudis "providedifor opening and closing contacts that control the rotation of the cam. St'ud s TI in pojsitions 2- 9 are "all-of the same'length and'epen contacts 78 and 79 (Fig. 5) which stop the corresponding cam when rollers 51 and58 are'centered ina-position. From position I fthomingposition) of each cam a stud 85' projects which is longer than studs i1 and operates contacts iiiand 82 (Fig. 5) as well as? and T9. jSt'uds 80*sirnu'ltaneously close upper contacts of 8 l' and- 82 and open contacts 78 and 79. Thus horne position-of "a cam marked by the closing or upper-8| or 82 and opening'of 18 or 19. I a e The electrical control of {the machine will now be explained with theaidof- Fig. '5. When-lever 21 ismoved into the operative-position, ground at central'portion-2 of spring I is connected in parallel 'over'shoes H and I2, tips'22'and 23, Windingfi 9i 13 36753 a 34 1 9 r u e t These relays energize' and light lamps -85and 86 which are 'conspicueusiy-=piaeea an framework 46 on either side of lever 21, T h e movement of lever 21 from the raised tothe loweredpo'sition closes lower contactsf ilfl and 83, Projection 89 (Fig. 3) =01: "lever zi-j 'ont qi -th op'etlngfand closing of these contacts Solenoid*-'35 is initially energized fover,fro nt eon 9 H ela'ysf8 3 -5r"84, lower eontacts -fij;or"88 to"ground at el br sa and armature -34 flocks lever 21 sewn. *-Mag'iiets 90 and '9] u of clutches 65aiiclf'lli; are energized'wh'en the lowercontac 1 andfldareclosed. Clutch magnet 9| is nerg ed from attery =at' holding keysz-magne'tfllllf nd rela anparallel, lower contact; 88; u gr -'ceht cesz; round. The energizi'ng circuit ffor ciuftc'h et"9Itisiihildrto that of mag'net" s {except-tha 3.1-; is over relay-' 9s, low'er contact 8T"an d-upp'er contact '8 l. n iis aii i i what-ma as am r nom ositmn to position, only the righthand s ide Q? he ma h ne w llh ref r e m but it Shmihfbe keptin rnindthat the left hand side operates in I Wf h sme yvhile 'rnagnet '9 I and they 94 -are-ehergiz'ed as above described, metastases-sut srpasiuta-l 8 u e eli e *3?""lW i i i l nected "to 19 which replaces-82 *as 'grou'fid for magnet 9 I. As roller 58 rides up one side ofcamming surface 16, plunger 25 pushes arm I and shoe l2 out of contact with tip 23, relay 84 deenergizes but solenoid 35, previously energized over front contacts 84, remains energized by finding ground over front contact .of relay 94. As roller 58 starts down the other side of camming surface 16, plunger 25 is pulled down and out of engagement with arm 1 byspring 54. If shoe |2 can still make contact with point 23, relay 34 once again energizes, magnet 9| is kept energized over front contacts of relay 84 when ground is removed at contact 19 by stud ll, and the cam moves into position 2. Plunger 25 is again driven up but this time a little higher by camming surface 16 and the circuit of 84 opens again.

Assuming that arm 1 has been sufiiciently detensioned by the last mentioned blow of plunger 25, shoe |2 will not contact point 23 when the plunger is withdrawn. Therefore, solenoid 35 is momentarily deenergized since neither relays 84 or 94 is energized. Armature 34 releases and lever 21 moves to the raised position and closes upper contacts 81 and 88 by projection'89. Cam 58 not being in home position is then driven through the remaining positions until home position is reached over the following circuit: ground, lower contact 82, upper contact 88, magnet 9| and relay 94 in parallel, key 92, ground. 7 Front CQII. tact of relay 94 energizes solenoid 35 which now functions as a lock out for lever 21 as above mentioned. When cam 60 reaches home position, stud 88 opens 82 lower and closes 82 upper. The solenoid and clutch magnet deenergize and, the machine is now ready for another brush spring. Thus four parallel paths for energizing the cir-; cuits of clutch magnets 90 and 9| are provided, namely, battery, key 92, magnets 98 or 9| in parallel to relays 93 or 94, contacts 18 or 19, ground; battery, key 92, magnets 99 or 9| parallel to relays 93 or 94, lower contacts 81 or 88, upper contacts 8| or 82, ground; battery, key 92, magnets 99 or 9| parallel to relays 93 or 94, contacts 83 or 84, contacts 93 or 94,- ground; battery, key 92, magnets 98 or 9| parallel to relays 93 or 94, upper 8'! or 88, lower 8| or 82,- ground. f H

There are two parallel energizing paths for the circuit of solenoid 35, namely, battery, solenoid 35, contact of relays 83 or 84, lower contacts, 87 or 88, upper contacts 8| or 82, ground; battery, solenoid 35, contacts 93 or 94 ground. According to the last mentioned path it will be seen that as long as either clutch magnet 98 or 9| is operating, as indicated by corresponding parallel relays 93 or 94 being energized, solenoid 35 will be energized and its armature performing either its lock out or look in function.

Usually a brush will be detensioned after a cam has passed through two or three positions and the brush has been struck by the plunger two or three times. The detensioning of each shoe is independently performed, and plunger 24 may stop operating while plunger 25 continues.

The machine may be used to perform certain testing operations on springs. For instance, if an operator of a machine notices that, after a spring has been clamped in detensioning position, one or both of indicator lights 85 or 86 fails to light, she knows that the arm on the side of the machine corresponding to the light has insufficient tension. In order to check the actual tension of the spring, she throws a catch (not shown) which looks lever 21 in the lowered position independently of solenoid 35. The circuit of 6? the clutch magnet is opened at key 92 to prevent operation of the machine when contact between shoes II and I2 and. tips 22 and 23 is made. Gauges 42 and 43 are then rotated to decrease the pressure exerted by arms 40 and 4| until both shoes make contact with 22 and 23 as indicated by the lighting of lamps and 86.

Although the invention has been described with reference to a specific embodiment thereof, it will be understood that it is not restricted thereto but is limited in scope only by the appended claims.

- What is claimed is:

,1. In a machine for detensioning the two ends of a flat spring, in combination, a holder having an opened and closed position to receive and fix the spring intermediate its ends, a plunger for each spring end, cam means having a home and a plurality of operating positions for actuating each plunger to, deliver repeated detensioning blows to the corresponding spring end, a tension gauge for each end of the spring, mechanism actuatable by each gauge through the intermediary of the respective spring end for controlling the. cam of the plunger cooperating with the corresponding spring end, a magnet for locking the holder, an armature for said magnet adapted to engage the holder while it is closed, and means controlled by said armature for preventing the holder from closing while the cams are in operating positions. a 2. The combination according to claim 1 and in which each cam has a plurality of progressively raised surfaces between successive positions, said surfaces being adapted to actuate the corresponding cam.

3. In a machine for detensioning two shoes of a brush spring, in combination, a holder for fixing the spring intermediate its shoes, a spring pressed plunger for each shoe adapted to deliver blows thereto which detension it, a cam having a home and a plurality of operating positions to move a plunger into engagement with a shoe, a drive shaft, two driving clutches for coupling the shaft to the cams, an adjustable pressure gauge for each shoe adapted to engage a shoe near its end and exert pressure thereon, a contact pin for each shoe projecting through the holder so as to make contact with the respective shoe, adjacent its point of engagement by the gauge, when the shoe by the inherent tension of the spring overcomes the pressure exerted by the gauge, an operating magnet for each clutch, a circuit for 7 each magnet including the corresponding shoe and contact pin, a magnet having an armature for locking the spring in the holder, and a circuit for the last mentioned magnet closed while either shoe contacts its pin and either cam is out of its home position.

4. The combination according to claim 3 wherein a path of the circuit for the last mentioned magnet is jointl controlled by the first mentioned magnets.

5. In a machine for detensioning two shoes of a brush spring, in combination, a holder for fixing the spring intermediate its shoes, a lever attached to said holder for opening and closing the holder, a spring pressed plunger for each shoe adapted to deliver blows thereto for detensioning the shoe, a cam having a home and plurality of operating positions for each plunger adapted repeatedly to move the plunger into engagement with a shoe, a stud in the center of each position of each cam, adrive shaft, a driving clutch for each cam, an adjustable pressure gauge for each 7. shoeadapte'd to engage a shoe-nearits end and exert pressure thereon, -a contact pin :ror -eaeh shoepm ecting through the holder so as to contact the respective shoe,- adjacent its point o'f -e'ng'age'me'rit by the gauge, when thes'ho'e by the inherent tension of -thespring overcomes tne pressure exerted by th'e'g'au'ge,-an operating'magnot ier each' cl-lit'ch, a circuit for ach inagnet having four parallel e'nergiaing paths, the first path-including a! fir'St coritact controlled by the lever in' the closed position of the holder and a second contact controlled by a stud in the home position of a cam, the second path' in'cludiiig a centering con'tact controlld by each I stud, the third pa'th inclucli nga- 'contactcohtfoll'ed by the corresponding shoe or the brush spring and {a secondcontactcontrolled "by a relay in paiall'el tdishemagnet, the fourth: path including a fir'st contact controlled by thelever-in the open posinon of the holder and a second contact controlled by a' stud in the operating positions ofa-cam,=-a solenoid h'aving an armature for --locking the holder opened or closed, and a circuit for the solenoidihaving two parallel "energizing paths-the firsti'path jointly icontrolled by the contacts f two *relayseach inlparallel to a'co'rresponding clutch-magnet, the second path including A a first contact'controlled by a shoe and'a second contact controlledbythe lever,-and a third contact controlledby a-stud. V

6. The combination according to claim 5,-and'in which a manually operable key is included-I in the circuitsof the clutch magnets, and a lamp is included in the path of each shoe.

7. Insadevice foriadjusting the-tension in flat contact springs, each having a portionsthereof bentin' a predeterminedeposition' such as to overten'sion'the same,- a pressure gauge, a holder 'for engaging-a spring as aforesaid-andarranged so that the gauge will engagethe overbent portion of'the :spring and tend to-deflect said portionof the-spring against itsinherent "tension, in a: given direction from said predemrmined' position, a plunger adapted to deliver repeated blowsin-successive-cyclesto saidportion in such manner as to deflect said :portion in the saiddirection;-mechanism arranged to drive said plunger through one cycle at a time, 1 and con-trolmeans respon- 8 siii'to sa-idsiiring when engaged in said 'holder for initiating theiopration of a said I mechanism through one cycle.

8; The combination accordingtoclaim 7 whereinsaid hold'er has' an operative and an inoperativeipo's'itiom 'said-control means being further rsponsive to said holder occupying said operative position.

9.-Thecombinationaccording to claim 7 wherein sa'id mechanismcomprises a cam adapted to impart progressively larger movements to said plunger 4 during successive 4 cycles.

10. The -co'mbinati'on according to claim *9 wherein sa id cam has a homing -position' and a plurality --of ofi nori'nal positions and wherein s'aid' holder has 'an operative-and an inoperative position, means operablein the inoperative position of said holder and any off-normal position of'said cam for advancingthe-satiric toward its home position.

-1-1. T-he combination according to the claim 10 wherein saidelectromagnetic means is-also arranged tomaintain said-holder in said inoperative 5 position.

l2. The combination according to claim 7, comprising a stationary support for said holder and mounting'means pivotally securing said pressure gau'g'e to said support whereby the gauge may berotated-relativeto the saidpart, said pressure gauge comprising a member adapted upon such 3 rotation to exert 'a varying pressure upon saidpart.

13. The combinatlon according to claim 1-2, further comprising stop means for limiting the angleof r'otation -of said vpressure gauge and, thereby, the-range-of pressures exertable upon said part.

GERALD DEAKIN.

REFERENCES CITED The following references are of record in the file of this ipatent:

"UNITED STATES PATENTS Number y Name Date i 2,355,468 R0151) Aug. 8, 1944 further comprising electromagnetic 

